Metal hatch pontoon



. Jan. 15, 1952 K. W JERNSTROM 2,582,436

METAL HATCH PONTOON Filed June 5, 1947 2 SHEETS-SHEET l 1952 K.W.JERNSTROM METAL HATCH PONTOON Filed June 5, 1947 2 SHEETS-SHEET 2INVENTOR. 4452 d P/wT/Pwv A TTOR/VD S Patented Jan. 15, 1952 METAL HATCHPONTOON.

Karl W. Jernstrom, Verona, N. J asslgnor to Seaboard Machinery Corp.,New York, N. Y., a corporation of New Jersey Application June 5, 1947,Serial No. 752,734

This invention is a metal hatch pontoon having the advantages over priorart pontoons, of lighter weight, so it may be handled more easily,combined with an economically sound manufacturing cost and the abilityto adequately meet the specifications for ship hatch pontoons set byrecognizedagencies, that must pass on naval architecture, such as theAmerican Bureau of Shipping. a r

Certain of the broader phases of the present invention are disclosed andclaimed in a copending application filed June 5, 1947, by the sameinventor and entitled Metal Hatch Boards," said application bearingSerial No. 752,733.

A specific example of this metal hatch cover pontoon, having theadvantages and meeting the conditions noted, is illustratedby theaccompanying drawings in which:

- 4 Fig. l is a perspective view showing the use of the pontoon; Fig. 2is a top view of the pontoon;

Fig. 3 is a cross section taken from the line 3-3 in Fig. 2; 1

- Fig. 4 is a longitudinal section taken from the line 4-4 in Fig. "3;and v Figs. 5 and 6 are perspective views of details of the pontoon.

More specifically, these drawings illustrate a ship hatch cover pontoonmade of metal and comprising two substantially rectangular channels eachhaving a web I and flanges 2, arranged mutually parallel with theflanges of one extending towardsthose of the other in mutually spacedalignment at similar web side edges. The flange side edges 3 of each ofthese channels and remote from the web I, are integrally provided withflanges 4 rectangularly extending from these flange side edges 3 towardthe channel center and terminating in mutually spaced relation, in eachinstance to define with the channel a rectangular .box section having alongitudinal slot 5 giving access to its interior.

The second-named flanges 4 are substantially thicker than the web I, inthe case of each of the channels, and a channel having a web 6 andflanges 7, is arranged with its web 6 flush with an aligned two of thefirst-named flanges 2 and with its flanges 1 extending in the samedirection and contacting and being fastened to the second-named flanges4 extending from said two of the first-named flanges 2. The flanges 4and I are interfastened by screws and nuts 8.

Because the flanges 4 are thicker respecting the web I, eachlongitudinally slotted box section provided by the first-named channelsand 1 Claim. (01. 189-46) their parts, has approximately the samestrength as a fully closed box section of conventional con struction,while providing the advantage of the slot 5 which afiords access to itsinterior. A critical improvement, this being the equality of thestrength of a fully closed box section of conventional design, isobtained by making the flanges 4 with thicknesses greater than requiredto make their cross-sectional areas equal that of the channel web I ofwhich they are parts. This is of particular advantage when these webs Iare wider than their first-named flanges 2.

The maximum thicknesses of the flanges 4 should be kept within reasonconsistent with obtaining the objective of a strength comparable to afully closed box section. To provide an "example, when the flanges 4 areapproximately each one-third as wide as the web I, they should be madeapproximately two times as thick as the web.

Due to the composite construction of this new pontoon, all of the partsrequired to produce a pontoon of adequate size, such as oneapproximately 14 wide, 12 long and having a depth of a trifle more than8%", may be produced with the parts individually of such size as willpermit them to constitute light-metal alloy extrusions, as exemplifiedby high strength corrosionresistant aluminum or magnesium alloyextrusions. This permits the making of the flanges 4 thicker than thewebs l and flanges 2 with all these parts integral, and the flanges 6and I may be made of integral parts. A factor of great importance isthat this results in all the parts being substantially free from atransversely strained grain structure, which would be greatlydetrimental to the carrying of beam stresses by the pontoon. Anystraightening of the extruded parts may be done by stretching, whichdoes not introduce transverse strain to the rain structure of the metal.Incidentally, strain in the grain structure may be microscopicallyobserved by any competent metallurgist, so its presence and direction isdeterminable.

Each end of the pontoon is closed by a lightmetal alloy end castingcomprising a web 9 having slots l0 fitting around the flanges 4 and 1 sothat the web 9 can be positioned flush respecting the pontoon end. Aflange H surrounds the entire periphery of the web 9 including its slotsl0, this flange fitting inside the pontoon end and being riveted or spotor plug welded to the latter. Other forms of end closures may be used,but the one just described is particularly preferred.

The lateral stability of the pontoon is increased by a plurality ofstrut plates, each providing an upstanding wing l2 that projectsupwardly between the flanges 1 and is provided with a flange l3 fixed tothe web 6, each strut plate also having laterally projecting Wings 14which extend beneath the flanges 1 to the web I where they arefastenediby 'end Jflanges I1 5 on the wings ifll. 'I'he strutplate'flanges maybe fastened as indicated, by means of rivets or by spotor plug welding. The stiffness of the plate 12 is increased by :a bottomflange 16.

The necessary handles are generallyindicated by 11, these beingpreferably =.of .the flush type and welded or riveted in place. Thenecessary apertures in the web 6 for the basins of these handles do notmaterially affect the structural properties of the pontoon, particularlyif the handle basin is peripherally welded or riveted-to-;the peripheryof its hole in the web 6.

slitsmay now :be appreciated that this: invention provides a :pontoonwhich can be produced at ,an :economicallysound cost, yet onewhichisexcep- :tionally light weight-in character and Whichhas muchgreater corrosion resistance than when -made.;from, steel, for example.The described box :sections are of ;great.strength, yet they provide180C955 slots permitting the fastening .of the screws andnuts- 8mandntheinstallation :of plates 9.

,Rivetinginay be reasily accomplished-by .theuse of appropriate .blindrivets. .The beam strength of the pontoon meets allstandardrequirements. :All the extruded parts can be made by presentlyavailable equipment because the design of the pontoon permits theindividualparts to be vkept within the limits of conventional extrusion;presses. If the screws and nuts '8 are made of rsteeL-they should beheavilygalvanized or. cad- ;miumplated, and the rivets :should beof thementioned light-weight alloy.

I claim:

:A metal ship .hatch "pontoon comprising two substantially rectangularchannels each having :a web and flanges, :arranged mutually parallel:with the-flanges -,of one extending toward those of the other inmutually spaced alignment at similar web side edges, with the flangeside edges, of each of said channels and remote from the web integrallyprovided with flanges rectangularly extending from said flange sideedges toward the channel center and terminating in mutually spacedrelation, in each instance to define with :the \channel ;a :arectangularbox section having a longitudinal slot giving access to its interior,and a channel having a web and flanges, arranged with its Web flush withan aligned two of the firstnamedflanges and its flanges extending in thesame direction and contacting and being fastenedtotthe'secondnamedflanges extending from said itwo of the first namedflanges, said second-named flanges of said first-named channels, havingthicknessesgreater than required to make their total cross-sectionalarea equal that of the channel web of which they are parts, the webs ofsaid first-named channels being wider than their flrst spacedlongitudinally of said channels.

KARL -W. .JERNSTROM.

REFERENCES CITED The following references are of record in the fileofthis patent:

UNITED STATES "PATENTS Number Name Date 426,559 Dithridge Apr..29,;1890835,578 Tanner Nomi-3, 1906 1,085,429 ,Kahn etial. Jan. ,27, 1-9141,777,879 Ewe'rtz et a1. Oct. 7,1930

1,986,998 Burgess et a1. Jan. 8,1935 2,101,056 .Frick l .Dec. 7,19372,485,165 Pollman Oct.18, 1949

